What is the most important information I should know about nitroglycerin?

You should not use this medicine if you are also using medicine to treat pulmonary arterial hypertension (PAH).

Do not take erectile dysfunction medicine (Viagra, Cialis, Levitra and others) while you are taking nitroglycerin, or you could have a sudden and serious decrease in blood pressure.

You should not use sublingual nitroglycerin if you have severe anemia (low red blood cells), if you have a condition that causes increased pressure inside the skull (such as a head injury or brain tumor), or if you have symptoms of circulation problems or shock (pale skin, cold sweat, fast or irregular heartbeats, sudden weakness or feeling like you might pass out).

Seek emergency medical attention if you have early symptoms of a heart attack (chest pain or pressure, pain spreading to your jaw or shoulder, nausea, sweating, general ill feeling).

What should I discuss with my healthcare provider before taking nitroglycerin?

You should not use nitroglycerin if you are allergic to it, or if:

you are using medicine to treat pulmonary arterial hypertension (PAH), such as riociguat (Adempas), sildenafil (Revatio), or tadalafil (Adcirca).

Do not take erectile dysfunction medicine (Viagra, Cialis, Levitra, Stendra, Staxyn, sildenafil, avanafil, tadalafil, vardenafil) while you are taking nitroglycerin. Using erectile dysfunction medicine with nitroglycerin can cause a sudden and serious decrease in blood pressure.

You should not use sublingual nitroglycerin if you have:

severe anemia (low red blood cells);

a head injury, brain tumor, or other condition that causes increased pressure inside the skull; or

To make sure nitroglycerin is safe for you, tell your doctor if you have:

congestive heart failure;

heart rhythm disorder (especially if you take medicine to treat this condition);

a history of heart attack, stroke, or head injury;

low blood pressure;

glaucoma;

migraine headaches; or

if you are dehydrated.

It is not known whether nitroglycerin will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.

It is not known whether nitroglycerin passes into breast milk or if it could harm a nursing baby. Tell your doctor if you are breast-feeding a baby.

How should I take nitroglycerin?

Follow all directions on your prescription label. Do not take this medicine in larger or smaller amounts or for longer than recommended. If you use too much nitroglycerin, the medicine might stop working as well in controlling your symptoms.

Nitroglycerin is usually taken at the first sign of chest pain. If possible, try to rest or stay seated when you use this medication. Nitroglycerin can cause dizziness or fainting.

You may use nitroglycerin sublingual within 5 to 10 minutes before an activity you think might cause chest pain. Follow your doctor's instructions.

Do not crush, chew, break, or open an extended-release capsule. Swallow it whole.

The nitroglycerin sublingual tablet should be placed under your tongue and allowed to dissolve slowly. Do not chew or swallow it. You may use additional tablets every 5 minutes, but not more than 3 tablets in 15 minutes.

If you use nitroglycerin sublingual spray to treat an angina attack: At the first sign of an attack, apply the spray directly on or under your tongue. Close your mouth after each spray. Do not inhale the spray. Do not shake the spray before or during use. You may use additional sprays every 5 minutes, but not more than 3 sprays in 15 minutes.

Seek emergency medical attention if your chest pain gets worse or lasts more than 5 minutes, especially if you have trouble breathing or feel weak, dizzy, or nauseated, or lightheaded.

You may feel a slight burning or stinging in your mouth when you use this medicine. However, this sensation is not a sign of how well the medication is working. Do not use more medication just because you do not feel a burning or stinging.

This medicine can cause unusual results with certain medical tests. Tell any doctor who treats you that you are using nitroglycerin.

If you take nitroglycerin on a regular schedule to prevent angina, do not stop taking it suddenly or you could have a severe attack of angina. Keep this medicine on hand at all times in case of an angina attack. Get your prescription refilled before you run out of medicine completely.

Store the tablets in the glass container at room temperature, away from moisture and heat. Keep the bottle tightly closed when not in use.

Keep the spray away from open flame or high heat, such as in a car on a hot day. The canister may explode if it gets too hot.

What happens if I miss a dose?

Since nitroglycerin is taken as needed, you may not be on a dosing schedule. If you are taking the medication regularly, take the missed dose as soon as you remember. Skip the missed dose if your next dose is less than 2 hours away. Do not take extra medicine to make up the missed dose.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222. An overdose of nitroglycerin can be fatal.

What should I avoid while taking nitroglycerin?

This medicine may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be alert. Avoid getting up too fast from a sitting or lying position, or you may feel dizzy. Get up slowly and steady yourself to prevent a fall.

Avoid drinking alcohol. Alcohol can lower your blood pressure, and may increase some of the side effects of nitroglycerin (dizziness, drowsiness, feeling light-headed, or fainting).

Nitroglycerin side effects

Get emergency medical help if you have signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Seek emergency medical attention if you have symptoms of a heart attack, such as:

chest pain or pressure;

pain spreading to your jaw or shoulder; or

nausea, sweating, general ill feeling.

Nitroglycerin can cause severe headaches, especially when you first start using it. These headaches may gradually become less severe as you continue to use nitroglycerin. Do not stop taking this medicine. Ask your doctor before using any headache pain medication.

Call your doctor at once if you have:

severe or throbbing headaches that do not become less severe with continued use of nitroglycerin;

pounding heartbeats or fluttering in your chest;

slow heart rate;

blurred vision or dry mouth; or

a light-headed feeling, like you might pass out.

Common side effects may include:

mild burning or tingling with the tablet in your mouth;

headache;

dizziness, spinning sensation;

nausea, vomiting;

flushing (warmth, redness, or tingly feeling);

pale skin, increased sweating; or

feeling weak or dizzy.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What other drugs will affect nitroglycerin?

Many drugs can interact with nitroglycerin. Not all possible interactions are listed here. Tell your doctor about all your medications and any you start or stop using during treatment with nitroglycerin, especially:

aspirin or heparin;

a diuretic or "water pill";

medicine to treat depression or mental illness; or

ergot medicine to treat migraine headache, such as dihydroergotamine, ergotamine, ergonovine, or methylergonovine.

This list is not complete and many other drugs can interact with nitroglycerin. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Give a list of all your medicines to any healthcare provider who treats you.

Related treatment guides

Where can I get more information?

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Disclaimer: Every effort has been made to ensure that the information provided by Cerner Multum, Inc. ('Multum') is accurate, up-to-date, and complete, but no guarantee is made to that effect. Drug information contained herein may be time sensitive. Multum information has been compiled for use by healthcare practitioners and consumers in the United States and therefore Multum does not warrant that uses outside of the United States are appropriate, unless specifically indicated otherwise. Multum's drug information does not endorse drugs, diagnose patients or recommend therapy. Multum's drug information is an informational resource designed to assist licensed healthcare practitioners in caring for their patients and/or to serve consumers viewing this service as a supplement to, and not a substitute for, the expertise, skill, knowledge and judgment of healthcare practitioners. The absence of a warning for a given drug or drug combination in no way should be construed to indicate that the drug or drug combination is safe, effective or appropriate for any given patient. Multum does not assume any responsibility for any aspect of healthcare administered with the aid of information Multum provides. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the drugs you are taking, check with your doctor, nurse or pharmacist.